Subwavelength-thick modulation of surface profile of a dielectric layer combined with a nanometer-thick metallic coating on it can be used for highly sensitive refractive index sensing using the concept of surface plasmon resonance. The performance efficiency of a 1D sinusoidal plasmonic grating of higher periodicity made of polymethylmethacrylate with gold coating on it is evaluated for monitoring water quality. The sinusoidal structure is fabricated by the cost-effective soft imprint lithography technique using a commercially available compact disk as master. Even though the master has a step profile, the solution-based technique aids in achieving the sinusoidal profile. The higher periodicity aids in attaining a higher sensitivity of 1533 nm/RIU at normal incidence and also provides a broad wavelength detection regime that can be controlled by the incidence angle. As the sinusoidal grating supports only the fundamental mode of the surface plasmon, it allows for more precise detection of any analyte. The optimized parameters for the structure are obtained through finite element method calculation.

中文翻译：

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具有正弦轮廓的大周期等离子体光栅，用于高灵敏度监测水质

介电层表面轮廓的亚波长厚度调制与其上的纳米厚度金属涂层相结合，可利用表面等离子体共振的概念用于高灵敏度折射率传感。评估了由聚甲基丙烯酸甲酯制成的具有金涂层的较高周期性一维正弦等离子体光栅用于监测水质的性能效率。正弦结构是通过具有成本效益的软压印光刻技术制造的，使用市售光盘作为母版。尽管母版具有阶梯轮廓，但基于解决方案的技术有助于实现正弦轮廓。更高的周期性有助于在垂直入射时获得 1533 nm/RIU 的更高灵敏度，并且还提供可通过入射角控制的宽波长检测机制。由于正弦光栅仅支持表面等离子体的基本模式，因此可以更精确地检测任何分析物。通过有限元法计算得出结构的优化参数。